Petroleum lubricant product and method of making same



Patented ocean, 1936 PATENT OFFICE rn'rnonnum LUBRICANT PRODUCT AND ne'rnon or MAKING same Robert C. Moran, Wenonah, and William L. livers and Everett W. Fuller, Woodbury, N. 1., assignors to Socony-Vacnum Oil Company, In-

corporated, New York, N.

New York No Drawing. Application Serial No. 43,3

4Claims.

Recent changes in automotive engine design, tending toward higher bearing pressures, higher rotative speeds, higher engine temperatures, and the like, have occasioned departure from the use 6 or the usual bearing metals such as babbitt. The newer bearing metals are of different nature and, while harder, are in general more susceptible to destructive agencies of a corrosive nature. Typical of these newer bearings are those composed of o a cadmium-silver alloy supported upon a steel back, which are now widely installed in certain makes of automobiles. Others of these relatively new bearing metals which may be mentioned are cadmium-nickel and copper-lead alloys.

These changes in engine design have been concurrent with marked advances in methods of refining lubricant. oils for automotive use. The demand for oils having lesser changes in viscosity with temperature change; i. e.. higher viscosity index (V. I.) has been met by refining lubricants intended for motor oils by certain solvent refining or solvent extraction processes, wherein advantage is taken of the selective solvent power for hydrocarbons of various typeswhich is possessed by certain liquid reagents, for example, dichlorodiethylether, cresylic acid, phenol, chioraniline,

chlorophenol, phenetidine, benzyl alcohol, nitrobenzene benzonitrile, furfural, aniline, benzyl acetate, liquid sulfur dioxide, mixtures of liquid sulfur dioxide or aniline with benzol, and the like.

These solvent refining processes are operated to concentrate in the desired lubricant traction those compounds of a paraflinic nature possessed of the ability to suifer only a small change of viscosity upon change of temperature, and to reject the compounds of naphthenic nature which do suffer such change of viscosity to a more marked degree. These refining processes have enabled supply of an oil of quite desirable general characteristics, definitely far superior to any oil previously produced from mixed base or asphaltic crudes, and superior to a like, though lesser, de-

gree over oils previously produced from paraifine base crudes.

It has been found that the solvent refined motor oils referred to above are for some reason definitely corrosive to the newer bearing metals under normal conditions of automotiveuse, sometimes resulting in bearing failure after only a few 0 thousand miles of normal driving. It is further known that the same reaction, viz, corrosion of alloy bearing metals such as-cadmium-silver, also occurs in good paraflinic base oils which have not been subjected to solvent refining. The higher Y the V. I. of the lubricating oiLthemore pronounced Y., a corporation of October 3, 1935,

is the tendency to corrosion of the kind referred to above. Generally speaking, the problem is encountered in oils having a V. I. of or higher, and becomes important in oils having a V. I. of to or higher, and very important in oils of V. I. or higher.

It is an important object of this invention to provide means for satisfactorily inhibiting or preventing this corrosion from taking place to a serious degree. It is an object of this invention to alter or modify a highly refined motor oil, normally corrosive, by the use of an additive ingredient capable of substantially inhibiting this corrosion. It is an object to provide a substantially non-corrosive motor oil of high V. I. An object of this invention is to provide an additive reagent or ingredient capable of inhibiting the corrosive properties of these oils. The production of solvent refined oils of low corrosive properties under conditions of automotive use is a major object of this invention, as well as the method of production of such oils which couple high viscosity index with low tendency to corrosion.

This invention is based upon the discovery that addition to the oil of small amounts of triphenylphosphite (CcHsO)3P accomplishes the above objects. It is found that when corrosion of the type outlined above occurs, especially if the oil be one which has been produced by a process of solvent refining, in which type the corrosive properties appear to be the most marked, that the oil can be rendered substantially non-corrosive under conditions more strenuous than normal automotive use by the addition of controlled amounts of this compound, viz, triphenylphosphite.

Triphenylphosphite is an organic compound having the following graphic formula:

This compound may be prepared by the reaction of phenol and phosphorus trichloride, in the proportions of three molecular amounts of phenol to one of phosphorus trichloride. The reaction mixture is heated until the evolution of hydrogen chloride ceases. This evolution of HCl gas may be measured, since it furnishes a convenient means of estimating and controlling the progress of the reaction. The resulting product, triphenylphosphite, may be purified, if desired, by a process of fractional distillation, the pure compound boiling at 209-210 C. at 1 mm. mercury pressure. For the present objects it may be used either as produced or in the fractionated form, although the use of the fractionated compound is preferred. A satisfactory reaction product may be made by heating the reaction mixture, after the cessation of the evolution of HCl gas, to a temperature of 190 C. under a pressure of 1 mm. mercury (designated herein as Topped). By fractionation, this may be conveniently made to yield a product boiling at 205-215 C. at 1 mm. mercury pressure (designated herein as Fractionated") The following sets of data demonstrate the efiectiveness of this novel corrosion inhibitor. In all of these tests, the oil used was a solvent refined motor oil of SAE 20 rating, having a Saybolt viscosity of 56 seconds at 210 F., a flash point of 420 F., and a V. I. of 117. Actual motor operation tests are set forth in' Table 1, below, four comparative tests being given. In these tests, a motor oil blank and motor oil blends containing diiferent proportions of the novel inhibiting ingredient of this invention were subjected to test in a modified Delco knock test engine, equipped with bearings of cadmium-silver alloy on a steel back. The alloy is about 2.5% silver, a few hundredths of a per cent of copper, and the balance of cadmium. The motor was equipped with crankcase oil heaters to maintain oil-temperatures (330 F.) at least equal to those encountered under extreme conditions of automotive use. On each test the test engine was operated for 20 hours at a rotative speed the equiva-. lent of an automobile road speed of 60 miles per hour. In rough terms, each test is the equivalent of exposure of the oil to use in an automobile for 1200 miles of continuous 60 mile an hour driving, a condition far more rigorous than anyencountered in normal use. The hearings in the engine were new for each test, and were carefully weighed before and after to determine loss in weight. the used oil was measured, and is recorded as being indicative of the corrosive nature of the oil. The inhibitor used was the fractionated triphenylphosphite of 2052i5 C. boiling point at 1 mm. mercury pressure described above.

From this it may be seen that the use of this novel corrosion inhibitor, viz, triphenylphosphite, in amounts as small as one quarter of one per cent prevented corrosion to a substantially complete degree under conditions much more rigorous than any likely to be met in practice, while as little as one tenth of one percent reduced the bearing loss almost one half.

An indicative test of considerable merit may be made in the laboratory by suspending a portion of a cadmium-silver alloy bearing in a bath of the oil under test in a glass container, maintaining the oil at about 350 F., and passing air through the oil in contact with the bearing metal. Convenient conditions are: 30 gm. oil,2,000ml-. air per hour, 22

The neutralization number (N. N.) of

hours. The following table shows results of a series of such tests in which oils containing different proportions of triphenylphosphite, and an oil blank were tested, giving the loss in weight of the bearing metal, and the neutralization number of the used oil. The oil used was the same as in Table I.

TABLE II "Com sion tests in class '1 t l i NbNl es 038, m1 used ligrams on Oil Alone 30 l. 8 Oil 2.00% ingredient Fractionated) 1 0. 5 Oil 1.00 a ingredient Fractionated) 0. Oil .50 ingredient Fractionated)--- 0 0. 8 Oil 25%; ingredient Fractionated)--- 1 0. 8 Oil .10% ingredient Fractionated; 1 0. 5 Oil .05 ingredient Fractionated 8 1.0 Oil .10 ingredient Topped) 0 0. 15 Oil .05% ingredient Topped) 13 1. 2

From the combined evidence of the above exemplary data, it is evident that the novel corrosion inhibting' ingredient herein disclosed, namely triphenylphosphite, is an eflective agent for the prevention of corrosion of automotive parts, particularly the newer type alloy bearings, when introduced in proper amounts into an oil otherwise highly corrosive.

Visual examination of the bearings from engine tests such as those reported in Table I show the effectiveness of triphenylphosphite in a very marked manner. The bearing subjected to the oil blank shows plainly the effect of corrosion, very little of the original surface remaining. The bearings subjected to the inhibited oils show little or no visual evidence of corrosion. Similar visual evidence of the effectiveness of this inhibitor may be noted by inspection of the pieces of metal used in the tests in glass. It is preferred to use this ingredient, triphenylphosphite, in amounts ranging between 0.25% and 1.0% although for less severe services and in oils not highly corrosive, aslow as 0.10% may be fully efiective for the purposes intended.

This ingredient, triphenylphosphite, is a water clear oil, freely miscible with hydrocarbons, and may be added in any proportion without darkening or deepening the color of the oil. When so added, it has no tendency to separate from the oil under conditions of storage or use.

We claim:

1. A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is an alloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the efiectiveness of the lubricating oil by incorporating therein triphenylphosphite in a small but suflicient proportion substantially to retard the corrosion.

2. A method of lubricating bearing surfaces in internal combustion engines when subjected to conditions of operation which comprises maintaining between bearing surfaces, one of which is analloy formed chiefly of a metal selected from the class consisting of cadmium and copper, a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy. and

maintaining the eflectiveness oi the lubricating oil by incorporating'therein from 0.1% to 1.0% of triphenylphosphite suflicient substantially to retard the corrosion.

3. A method of lubricating bearing surfaces which comprises maintaining between bearing surfaces, one of which is an alloy selected from the class consisting of cadmiumsilver, cadmiumnickel, and copper-lead alloys a film of lubricating oil which initially produces an effective lubricating action but which would normally tend to corrode the aforesaid alloy, and maintaining the effectiveness of the lubricating oil by incorporating therein triphenylphosphite in a small but suflicient proportion substantially to retard the corrosion.

ROBERT c. MORAN. WILLIAM L. EVERS. EVERETT w. FULLER.

Certificate of Correction Patent No. 2,058,342.

October 20, 1936 ROBERT C. MORAN ET AL.

I It is hereby certified that error appears in the printed specification of the above numbered patent requiring correct1on as follows: Page 1, second column, lines 38 to 44, mclus1ve, strike out the formula and insert instead the following:

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and'sealed this 23rd day of February, A. D. 1937.

[SEAL] HENRY VAN ARSDALE,

Acting Commissioner of Patents.

1 Certificate of Correction Patent No. 2,058,342. October 20, 1936 ROBERT C. MORAN ET AL.

I It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, lines 38 to 44, inclusive, strike out the formula and insert instead the following:

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 23rd day of February, A. D. 1937.

[SEAL] HENRY VAN ARSDALE,

Acting Oommissioner of Patents. 

